Telephone system



Aug. 18, 1942. L. 1'. MEEDS TELEPHONE SYSTEM Filed Feb. 1, 1941 9Sheets-Sheet l 1% w\ N N \Q\ I] ews Q #9 6R 5 HI P flfi 8.?! MHU gin U8% 2 mot mwt 5.0K h m but not Y0K N9 m ii 6Q mat GE QWNEGQQQ 6PlNVENTO/P LIME E 05 51 A T TORNEV Aug. 18, 1942. L. 'r. MEEDS 2,293,611

TELEPHONE SYSTEM Fil ed Feb. 1, 1941 9 Sheets-Sheet 2 FIG. 2

//V L. r M5505 W WT ATTORNEY Aug. 18, 1942. 1.. -r. MEEl DS 2,293,511

' TELEPHONE SYSTEM Filed Feb. 1, 1941 9 Sheets-Sheet 3 ATTOR g 18, 1942;L. 'r. MEEDS TELEPHONE SYSTEM 9 Sheets-Sheet 4 Filed Feb. 1, 1941INVENTOR .L. T MEEDS ATTORNEY Aug. 18, 1942. L. T. MEEDQ TELEPHONESYSTEM Filed Feb. 1, 1941 9 Sheets-Sheet 5 D0 oo /Nl ENTOR L. T M155054L ATTOR EV Aug. 18, 1942.

L.T.MEEDS TELEPHONE SYSTEM Filed Feb. 1, 1941 9 Sheets-Sheet 6 /NVENTO/?L. TMEEDS Aug. 18, 1942. 1... 'r. MEEDS TELEPHONE SYSTEM 9 Sheets-Sheet7 Filed Feb. 1, 1941 INVENTOR L. 7. M51505 W, 7 7%? ATTORNEY Aug. 18,1942. y L. T. MEEDS 2,293,611

TELEPHONE SYSTEM Filed Feb. 1, 1941 9 Sheets-Sheet 8 /NI/ENTOR L. 7'. MEE 05 A TTOR/VE V Aug. 18, 1942. L. T. MEEDS 2,293,611

TELEPHONE SYSTEM Filed Feb. 1, 1941 9 Sheets-Sheet 9 Q 0 a a & R [Q IHI-INVENTOR L. 71 MEEDS v MWMW ATTORNEY Patented Aug. 18, 1942 UNITEDSTATES PATENT OFFICE TELEPHONE SYSTEM Application February 1, 1941,Serial No. 376,961

15 Claims.

This invention relates to telephone systems and has for its object tofacilitate the testing of automatic telephone exchanges particularlywhen newly installed,

The vast number of connections made during the installation of anautomatic telephone exchange require a thorough test of every part ofthe exchange before placing it in service. However, satisfactoryindividual tests may not result in satisfactory operation under serviceconditions, since the trafiic load is a factor of great im portance inthe ability of an ofiice to function.

In accordance with the present invention, means is provided to simulateservice conditions by originating a large volume of calls over a groupof lines and directing the calls to a variety of destinations inproportion to the expected service load.

By this means it becomes possible to determine whether the equipmentwill handle the expected maximum trafiic with the proper margin ofsafety from the standpoint of condition, quantity and distribution ofthe circuits involved.

In addition, the call originating means of the present inventionsupplements the special circuit test equipment by creating a conditionof service under which the individual pieces of equipment must function.

A further advantage provided by this call originating means may be foundin the training given the maintenance force in the handling of troubleswhich may arise or may be artificially produced.

Specifically the invention provides means for seizing a plurality ofline terminals one at a time and originating a call thereover. After aninterval the lines are successively connected to a plurality of dialingmeans which are arranged to transmit different designations over eachline.

Subsequently, each set of line terminals is seized 4.

to simulate disconnection. Means is provided for determining theintervals between each seizure of given line terminals together withmeans for maintaining the intervals for all of the lines.

The means for seizing the line terminals com- L prises a plurality ofrotary switches each of which has access to all of the lines. Manualmeans is provided for starting each switch, after which the switchesadvance in synchronism so that a different plurality of lines are actedon at each step.

The invention will be more clearly understood from a consideration ofthe following description in connection with the accompanying drawings,in which Figure 1 shows the switch which controls the dialing of thethousands and hundreds digits, and two sets of line terminals;

Fig. 2 shows a switch for dialing the tens and units digits as well ascertain control relays;

Fig. 3 shows the code dialing switch;

Fig. 4 shows the line seizure controlling equipment;

Fig. 5 shows the switches which connect with the line terminals;

Fig. 6 shows the numerical dialing control relays;

Fig. 7 shows the relays which start the number dialing;

Fig. 8 shows the control keys;

Fig. 9 shows the I synchronizing relays; and

Fig. 10 shows the arrangement of Figs. 1 to 9.

This call originating circuit is particularly designed for testing thecross-bar type of telephone system such as disclosed in U. S. PatentsNo. 2,235,803, to W. W. Carpenter, March 18, 1941, and No. 2,232,371, toJ. W. Dehn et al., February 18, 1941, but is equally applicable to othertypes of dial telephone systems.

Before starting the use of the call originator, fifty sets oforiginating line terminals are selected and connected with fifty sets ofterminals such as terminals I03, HH and I20, l2l in the call originator.In addition, forty-four telephone designations are selected and thebrushes of switches 550, 560 and 510 are cross-connected to switches359, I50 and 250 in accordance therewith. By spreading the linesselected over the originating equipment and selecting the designationsto include a variety of office codes and number groups, as well asoperator codes and unstand designations such as permanent signals, etc.,a traffice load closely resembling the actual expected service load canbe built up. For larger offices a plurality of these call originatorsmay be used to create a suflicient load.

The test circuit consists essentially of five integral parts whichfunction together as a single circuit unit. These five parts may becalled 1. Dial tone seizure circuit.

2. Office code dialing circuit.

3. Thousands and hundreds digit dialing circuit.

4. Tens and units digit dialing circuit.

5. Line disconnect circuit.

Each of these five circuits connects with a pair of line terminals insuccession and the interval between the connections of the five circuitswith any single line is dete n d by a ,key which conthan theintermittent load which is produced by test circuits which originate aplurality of calls simultaneously and may conveniently supplement theuse of the latter.

No means is provided in this circuit for checking the accuracy withwhich the connections are established. However, by connecting acondenser across the terminating line terminals corresponding toselected designations, to satisfythe marker, and preventing theoperation of the intercept relays, of; the terminating'markers, everycase of trouble will cause a record to be made by the trouble indicator.Since the" terminating trouble indicator gives the number called andidentifies the marker, the sender and the incoming circuit involved; thelarge volume of calls given by the call originator quickly brings outany circuit failures likely to signal wrong numbers.

Dial tone seizure circuit Referring now to the detailed functioning ofthe circuit; the operation is started by operating start key 880. Thiskey groundsconductors BM, 8112, and 833. Ground on conductor 81completes the circuits of relays I02, 206, and 300 which, beingconnected to a source of pulsating current, now begin to pulse ata rateof twenty-pulses per second. Ground on conductor B02; completes acircuit through resistance 4M and; the upper winding of polarized relayM10 to battery to hold the back contact of that relay closed. For asimilar purpose a circuit is closed by ground on conductor 802 throughthe upper winding of relay 20I and resistance 202 to; battery andthrough resistance Bill to theupper windingof relay 9% and battery. Inaddition, ground on conductor 8B2 completes a circuit for relay 402;Relay 2&3 operates in a circuit from battery through its winding overthe-back contact of magnet 55? or over the b ack contact of relay 294 toconductor 862, while relay $02. operates in a circuit from battery t hits winding, conductor 963, lower normal contact of key 894, backcontacts of magnets 521- and 511 to grounded conductor 882.

With relay 2M energized asrabove described, a circuit is'closed'fromground on conductor 803, left, normal contact of relay 26!, upperback contact of relay 2115, conductor 20%, uppermost back contact ofrelay 964, conductor EH5; winding of relay 'mfizand battery. Relay'Hiflcloses a circuit fromground onconductcr 6%!3, outer upper frontcontact of relay I00, conductor 'IOI, winding of magnet 5 31, whichcontrols switch 540, and battery and in" parallel with magnet 54'! over,the outerlower contact of relay 2%, normal contact and Winding of relay2%, resistance 291 and battery. Magnet 54! and relay 204 operate. Relay2M locks over its alternate contact, conductor 2E8, inner upper backcontact of relay 9M to grounded conductor 892. At thesame time relay204'closes a circuit from battery through resistance 269-, winding ofrelay 205; alternate contact of relay ZM-toground as above traced. Relay2G5 cannot operate, being shunted over its lower back contact by theoperating circuit of relay 2%. When magnet 54'! and relay 2% have bothoperated, the circuit for relay 2% is opened and that relay releases,permitting relay 235 to operate. The operation of relay Ell-5 opens thecircuit of relay Hill, causing that relay to release and release magnet54! to advance switch 548 to its first operative position.

When magnet 55? releases, relay 2% reoperates. Relay 263 now closes acircuit from ground through resistance ZIG, lower winding of relay 26 I,outer upper contact of relay 263, outer upper back contact of relay 2M,middle upper front contact of relay 2S5, brush 5 53, conductor 580,upper winding of line relay m3 and battery.

Relay Hi3 is individual to the line terminals Hill and till and is thefirst of fifty such relays whose corresponding line terminals have beenconnected to line terminals on the originating frames of the office.

If relay IE3 is normal relay ZGI receives surficient current in thecircuit traced to overcome the effect of the circuit through its upperwinding and therefore closes its right, operated, contact to operaterelay 2I2. Relay 2I2locks over its inner lower contact, inner upper backcontact of relay 2II to ground on conductor 802. Relay IE3 did notreceive sufficient current to operate in series with resistance 2H! butrelay 2:2, in operating, connects direct ground to the winding of relayZill in shunt of resistance lll, whereupon relay I33 operates. Relay I03connects resistance I64 across the terminals I06 and IGI therebysimulating the action of a subscriber in originating a call. It alsolights lamp N25 to indicate that the line terminals are in use. RelayI03 locks over its inner upper front contact to a contact of relay M32which supplies the locking ground for all of the line relays.

The locking ground of relay I93 shunts the Winding of relay 2ilI andcauses that relay to reclose its left contact under the influence ofits'upper winding. With relay 2B5 operated, the release of relay 2Mcloses a circuit from ground on conductor 8%, left contact of relay 20!,inner upper front contact of relay 2G5, inner upper front contact ofrelay 2I2, lower winding of relay 2II and battery. The operation ofrelay 2II indicates that a line relay has been found normal, has beenoperated and has been locked. Relay 2 looks through its upper windingand inner upper contact to ground at the outer lower contact of relay285 and in parallel therewith to ground at the outer upper contact ofrelay 2I2. At its inner upper back contact relay 2 opens the previouslytraced locking circuit for relay 2I2 but at its inner lower contact itcloses a second circuit from the looking contact of relay 2I2 toconductor 208 which extends over the inner upper back contact of relay904 to grounded conductor 852. Relay 2I2 is slow to release andtherefore remains operated during, the transfer of its locking circuit.

Since key 895 has not yet been operated, relay 2H in operating closes acircuit from ground on conductor 832, outer upper front contact of relay2H, conductor 3%, normal contact of key 895, conductor 965 to thewinding of relay 994 and battery. Relay @6 5 looks over its inner upperfront contact and conductor to ground at the inner lower front contactof relay 2I I. The operation of relay 984 indicates the completion of acycle, which at this time only included the simulated initiation of acall. Relay 904 lights lamp 901 as a visual indication of the end of thecycle and also operates peg count meter 908. Relay 904 opens theoperating circuit of relay 100 and the locking circuits of relays 204and 2 I2 causing these relays to release, followed by relays 205, 2| Iand 904. The slow release character of relay 2I2 delays the release ofrelays 2H and 904 for a definite interval,

When relay 904 has released, relay 100 reoperates and the switch 540 isadvanced to operate another line relay in the manner above described.Since the line relays lock to relay 402 which in turn operates directlyfrom start key 800, the line relays remain locked and the line closuresare maintained independent of the position of switch 540,

In the manner above described one line relay after another is operated,each placing a bridge across the corresponding tip and ring terminalscausing the automatic equipment to connect an idle sender and districtjunctor with the line terminals. When any desired time has elapsed,preferably one sufiicient to insure the connection of a sender with eachline, key 801 is operated and, since it is a non-locking key, is heldoperated until the lighting of lamp 901 indicates the end of a cycle.Key 801 grounds conductor 208 holding relays 204, 205 and 2I2 operated.These relays in turn hold relays 2H and 904. Key 805 is now operated tostart the functioning of the code dialing circuit. Key 801 is thenreleased and after relay 904 releases, relay 100 reoperates.

Office code dialing circuit The oilice code dialing circuit includesswitches 500, 550 and 350. With key 805 operated ground is connectedover conductor 909 to the first, second and third upper armatures ofrelay 100. Therefore, when relay 100 operates a circuit is closed overthe inner upper front contact of relay 100 to the winding of magnet 501and battery and over the second upper front contact to the winding ofmagnet 551 and battery and, in parallel therewith, through the upperwinding of relay 403 and battery. Relay 403 looks over its innerlowercontact, lower back contact of relay 404, conductor 405, thirdupper back contact of relay 904, conductor 909 to ground at the contactof key 805.

With key 005 operated the circuit of relay 203 extends, in addition tothe paths previously traced, over the inner lower alternate contact ofkey 005 and over the back contacts of magnets 501 and 551 to groundedconductor 802 so that these magnets must also operate before relay 203can release to bring about the release of relay 100 and the advance ofswitch 540. The release of relay 100 releases magnets 501 and 551 tostep switches 500 and 550 to their first operative terminals.

Relay 100 in releasing also closes a circuit from ground on conductor909, outer upper back contact of relay 100, outer lower contact of relay403, right, normal, contact of relay 400, back contact of relay 406 tothe winding of relay 401 and battery. Relay 401 locks in a circuit overits inner upper contact in parallel with relay 403 under the control ofrelay 904.

Relay 401 tests whether the first line relay has remained operated andlocked by closing a circuit from battery through resistance 408, lowerwinding of relay 400, outer upper contact of relay 401, upper backcontact of relay 404, brush 505 in its first operative position,conductor 58I, lower winding and inner upper contact of line relay I03,to ground at the contact of relay 402. With locking ground present,relay 400 operates, closing a circuit from battery through the windingof relay 409, outer lower front contact of relay 401, left, operated,contact of relay 400, outer lower contact of relay 403, outer upper backcontact of relay to ground on conductor 909. Relay 406 locks over itsinner upper front contact and the inner lower contact of relay 401 inparallel with relays 403 and 401.

Relay 40B connects direct battery in shunt of resistance 408 to thecircuit of relay 400 and the lower winding of line relay I03. The lowerwinding of relay I03 is opposed to the upper winding at this time andthe adjustment is such that with the increased current in the lowerwinding, the resultant magnetic flux is insufiicient to hold relay I03operated and it therefore releases. With the removal of the lockingground for relay I03, relay 400 also releases. However, the dialequipment is not released, since ground is connected to the ringterminal IOI over a circuit which may be traced from that terminal,through resistance I04, conductor I06, brush 503, lower contact of relay402, conductor 409 to ground at the outer upper back contact of relay30I When relay 400 releases, it extends the ground which was connectedas above traced to its armature, over its right contact, outer upperfront contact of relay 40B, inner upper contact of relay 403, conductor4I0, back contacts of relays 302 and 303 to the armature of relay 300which is pulsing at a rate of twenty pulses per second as previouslydescribed.

With the armature of relay 300 grounded the first subsequent closure ofits left contact completes a circuit over the inner upper back contactof relay 30!, winding of relay 304 and .battery. Relay 304 operates andlooks over its lower contact and the back contacts of relays 303 and 302to ground on conductor 4I 0. When relay 300 then closes its rightcontact, it extends ground over the upper contact of relay 304, lowerback contact and winding of relay 30I to battery. Relay 30! alsooperates, locking in parallel With'relay 304. With relay 30I operatedthe left contact of relay 300 is connected over the inner upper frontcontact of relay 30I to the winding of magnet 353, while the rightcontact of relay 300 is connected over the outer upper front contact ofrelay 30I to conductor 409 and the ring terminal IOI. When relay 30!operated it disconnected steady ground from that terminal but since theright contact of relay 300 is closed at the time that relay 30Ioperates, the ring terminal is grounded over the contact of relay 300.

As relay 300 pulses, therefore, it alternately operates stepping magnet353 and opens the ring conductor toward the dial equipment to transmitan impulse thereto. Relays 3M and 304 serve to prevent the transmissionof mutilated first pulses to the magnet 353 and the dial equipment. Inorder to determine the value of the digit to be transmitted, theterminals of brush 35! are crossconnected to the terminals of brushes553 and 554 in accordance with the selected designations. It may benoted that brushes 053 and 554. While connected in parallel are arrangedat degrees to one another so that only one brush is effective at a time.When brush 320i reaches the terminal cross-connected to the firstterminal of brush 553, a circuit is closed from battery through thewinding of relay 302, brushes 35I and 553,

lower back contact .of relay Z43, conductor 2H,

outer upper contact of relay 4-03, conductor 4! l, inner upper contactof relay 203 to ground at the outer upper front contact of relay 205.Relay 302 operates and looks over its inner lower front contact andoff-normal contact 355 of switch 350.

With relay 3E2 operated, ground is connected to conductor 409 to holdthe dial equipment. Relay 302 disconnects ground from the armature ofrelay 300 to stop the pulsing. It also closes an obvious circuit forrelay 303 which in turn closes a circuit from ground at its uppercontact, over oif-norrnal contact 356 to the winding of release magnet354 and battery, restoring the switch 350 to normal. With switch 350normal, contacts 353 and 355 are opened and relay 332 releases, followedafter an internal, due to the slow release character of relay 303, bythe latter relay. Relay 303 is made slow enough to allow time be tweendigits for the subscriber sender circuit relays to properly function andbe ready for the next digit.

When relay 303 operated it also connected ground to conductor 403. Inaddition, relays 302 and 303 open the locking circuit of relays 30! and304 thereby causing these relays to release and connect ground toconductor 903.

Relay 3.32 in operating closed a circuit from ground at its inner uppercontact, normal contact and winding of relay 2M to battery. Relay 2Mlooks over its alternate contact, conductor 2H3, third upper backcontact of relay 8104 to ground .over conductor 000. At the same contactrelay 2M closes a circuit for relay 293 but relay 2l3 cannot operate,being shunted at its upper back contact by the operating circuit forrelay 2 l 4. When relay 302 releases as above described, relay 2E3operates, opening the circuit over brushes 553 and 554 and connectingground to brushes 55! and 552.

When relay 333 recloses its back contact, the armature of relay 300 isagain grounded and relays 3M and 33 i operate followed by thetransmission of the second code digit. Relay 302 operates at this timeover brushes 35! and 53! to ground at the front contact of relay 2l3.Relay 303 is operated, relays 3t! and 360 released and switch 330restored to normal as previously described. With relay 2 l 3 operated,relay 332 closes a circuit from ground over the inner upper contact ofrelay 302, upper front contact of relay 2i3, conductor 2E0, lowerwinding of relay 434 and battery. Relay 004 closes a locking circuit foritself from battery through its upper winding and inner upper frontcontact, inner upper back contact of relay I to ground over conductor009.

With relay 404 operated, a circuit is closed from ground over the outerupper front contact of relay 400, brush 505, conductor 53!, two windingsof relay I03 in series to battery. In this circuit the current flow inthe lower winding of relay ltii aids that in the upper winding and relayI03 reoperates, locking as before. The operation of relay 403 also opensthe locking circuit of relays 403, 003 and 407 and these relays release.

In the meantime the next line relay has been operated and locked overswitch 5 and relay 2 operated as previously described. However, with key0&5 operated the circuit by which relay 2H operated relay 334 is open.When relay 404 has also operated, a circuit is closed from batterythrough the winding of relay 904, conductor 905, lower normal contactsof keys 808 and 800, lower front contact of relay 404, upper alternatecontact of key 805, conductor 80,0, outer upper front contact of relay2i l to ground over conductor 802. Therefore, both cycles must have beencompleted before relay 904 canoperate. Relay 964 performs the previouslydescribed functions .with regard to the dial tone seizure circuit. Forthe code dialing circuit it releases relays 2 l 3, 2 l4 and 434. Whenrelay 2E2 has released, relay 004 releases and after the previouslydescribed operations relay I00 operates to start a new cycle.

Thousands and hundreds digit die-Zing circuit Again any desirable numberof cycles is permitted to take place as indicated by the lighting oflamp 301. Key is again operated to prevent the release of relay H2 andwhen lamp 00'! lights, key 809 is operated to start the dialing of thethousands and hundreds digits. Key 801 is then released, permittingrelay 2l2 and the other relays to release.

With key 000 operated the circuit of relay 263 extends, in parallel withthe branches above traced, over the inner lower alternate contact of key805, outer upper contact of key 809 and the back contacts of magnets 5i!and 551 to grounded conductor 802. Therefore, relay 203 can release onlyif magnets 5537, 5H, 5H, 55'! and 551 have operated as well as relay 2%.At its middle lower alternate contact, key 80?! connects groundedconductor 832 to conductor 609, which extends through resistance T04 andthe lower winding of relay 05 to battery to hold the left, normal,contact of relay I05 closed.

When relay 103 operates, the circuits previously traced are closed, andin addition circuits are closed from battery through the winding ofmagnet 5!! to the inner lower front contact of relay I00 and frombattery through the winding of magnet 53'! to the second lower frontcontact of relay I00 and thence in parallel to ground at the inner upperalternate contact of key 803. Magnets 5H and 55? operate in synchronismwith the other magnets. Relay 300 also closes a circuit from ground onthe inner upper contact or" key 809 over the third lower front contactof relay 1'00, lower winding of relay 102 to battery. Relay 102 operatesand locks in a circuit from battery through its upper winding and uppercontact, conductor E03, upper back contact of relay 005, to ground onconductor 609.

When, subsequently, relay 130 releases, magnets 5l'l and 50'! in turnrelease, advancing switches 5| 0 and 563 into association with the lineterminals I00 and I05. At this time a circuit is closed from batterythrough the winding of relay 105, back contact of relay M67, and leftcontact of relay 1'05, lower contact of relay Hi2, inner lower backcontact of relay M0, to ground at the inner upper contact of key 8&3.Relay 7&5 locks to ground over conductor 7233 as above traced. Withrelay 106 operated, a circuit is closed from battery through resistanceH33, up per winding of relay Hi5, outer lower front contact of relay75-6, brush 555 to conductor 5? and the lower winding of relay I03. Asin the previously described circuit, if relay N33 is locked, relayoperates and closes a circuit from battery through the winding of relayT31, inner lower front contact of relay 106, right, operated, contact ofrelay E05, lower front contact of relay H 2, inner lower back contact ofrelay "930 to ground at the contact of key 809. Relay 70'! looks overconductor 103 and connects direct battery in shunt of resistance 108,releasing relay Hi3, which in releasing also releases relay N35. Thering terminal IOI of the first line is now connected over conductor I08, and brush 5I3, lowermost front contact of relay 402, lowermostcontact of key 809 to groundat the outer lower back contact of relay I!so that the dial equipment does not release.

With relay I released, ground is extended from the contact of key 009over the inner lower back contact of relay I00, lower contact of relayI02, left contact of relay I05, outer upper front contact of relay I01,conductor I09, back contacts of relays I08 and I09, to conductor H0 andthe armature of relay I02 which is pulsing at twenty pulses per secondas mentioned above.

The thousands and hundreds digit dialing circuit functions in the samemanner as the code dialing circuit, the first cycle of relay I02operating relays III and I01. Relays III and I0? lock to conductor II 0,relay I 01 connecting the left contact of relay I02 to the Winding ofthe step- .ping magnet I53 of switch I50 and connecting the rightcontact of relay I02 to the ring line terminal, at the same timeremoving the holding ground. The terminals of brush I5I arecross-connected to terminals of brushes 503, 564, 565 and 506 inaccordance with the selected designations. Therefore, when brush I5Ireaches the terminal cross-connected to the first terminal of brush 503a circuit is closed from battery through the Winding of relay I08,brushes I5I and 503, outer upper back contact of relay 60I, conductorBIO, inner lower front contact of relay 205, inner lower contact ofrelay 203 to ground.

Relay I08 operates and locks to off-normal contact I55, in turnoperating relay I09. tion, relay I08 grounds the ring conductor, anddisconnects ground from conductor IIO to arrest pulsing. Relay I09operates release magnet I54, restoring switch I50 to normal. Relay I08closes a circuit from ground at its inner lower contact, conductor II2,normal contact and winding of relay 002 to battery. Relay 602 looks overconductor 6, second lower back contact of relay 904 to groundedconductor 802. It also prepares the circuit of relay Bill which isshunted by the operating circuit for relay 802.

When switch I50 reaches normal, relay I 08 releases, permitting relay00I to operate. With relay 00! operated, the circuit of relay I08 overbrushes 503 and 504 is opened and a new circuit is prepared over brushes505 and 569, outer upper back contact of relay E03 and the outer upperfront contact of relay- Bill, to ground over conductor I I2 aspreviously traced.

When relay I08 releases, it opens the circuit of relay I09, whichreleases slowly to permit the sender functions to be completed. Whenrelay I09 closes its back contact, relay I02 becomes operative again andthe hundreds digit is sent out in the same manner as the thousandsdigit. When relay I08 operates following the hundreds digit, it closes acircuit from ground at its inner lower contact, conductor II2, innerupper front contact of relay Bill, to the windings of relays 603 and004. Relay 003 operates slightly later than relay 004 due to a shuntover the normal contact of relay 604 which opens as soon as the latterrelay operates. Relay 604 closes a locking circuit for itself and relay603 to conductor BI I.

Relay 004 at its upper armature disconnects ground on conductor 609 fromconductor I03, releasing relays I02, I00 and I01. When relay I00releases ground is closed from conductor 009, over the upper frontcontact of relay 604, con- In addiductor 6I2, back contact of relay I06,brush 5I5 is relay I00 to, in eifect,

to conductor 58I and the windings of relay I03 in series. As before,relay I03 operates and locks to hold the dial equipment.

With relay 603 operated a circuit is closed from ground on conductor 6I0over the outer upper front contacts of relays GUI and 603 to the windingof relay 9I0 and battery. Relay 9I0 locks to ground at the lowercontacts of relays GUI and 603.

The operation of relay 9I0 indicates the completion of the function ofthe third circuit unit. In the meantime relay 2 has operated to indicatethe completion of the cycle by the first circuit and relay 494 may ormay not have been operated by the termination of the sending of the codedigits. If relay 404 operates early it cannot cause the operation ofrelay 904, since the circuit by which the joint operation of relays 2Hand 404 operated relay 904 is now open at key 809.

It will be remembered that at the time the start key was operated, relay902 was operated. With relay 902 operated, the joint operation of relays2I I, 404 and 9I0 completes a circuit for relay 904 which may be tracedfrom battery through the winding of relay 904, conductor 905, lowernormal contact of key 808, inner upper contact of relay 9I0, uppercontact of relay 902, conductor SI I, inner lower alternate contact ofkey 809, lower front contact of relay 404, upper alternate contact ofkey 805, conductor 808, upper front contact of relay 2 to groundedconductor 802.

Relay 904 operates and advances the three circuits to the next cycle aspreviously described. In 6cnperating, relay 904 also releases relays GMto 4.

Again the circuits are permitted to advance through a few cycles, afterwhich hold key 801 is operated to arrest the operation and, when lamp90! lights to indicate the end of a cycle, key 804 is operated and keyreleased.

Tens and units digit dialing circuit With key 804 operated the circuitof relay 902 is opened and that relay releases. Key 804 also extends thecircuit of relay 203 over inner lower alternate contact of key 804, andthe back contacts of magnets 521 and 51! to grounded conductor 802 sothat these magnets must also operate prior to the release of relay 203.At its upper alternate contact, key 804 connects grounded conductor 802to conductor 3I0, resistance 220, the upper winding of relay 22I andbattery,holding the armature of that relay against its normal, right,contact. In addition it connects battery through relay 305, overconductor 309 and the outer lower alternate contact of key 804 toconductor 9I5 in parallel with provide additional contacts for relay100.

When relay 305 operates, in parallel with relay I00, it connectsconductor 802, over its lower contacts to conductors 301 and 308,operating magnets 52! and 571. In addition, it closes a circuit frombattery through the lower winding of relay 309, upper front contact ofrelay 305, conductor 3I0, upper contact of key 804 to grounded conductor802. Relay 309 operates and locks in a circuit from battery through itsupper winding and upper front contact, conductor 3I I, upper backcontact of relay 608 to ground over conductor 3I0.

When relay 305 releases, switches 520 and 510 step to their firstoperative positons. Relay 305 also extends ground from conductor '3l'9,over the back contact of relay 305, lower contact of relay 309,conductor 3H2, right contact of relay 22!, back contact of relay 22-2,winding of relay 223 and battery. Relay-223 locks to conductor 3!! andconnects ground over its outer lower contact, outer upper back contactof relay 224, brush 523, to the ring conductor I56 to hold the dialequipment. Relay 223 also connects battery through resistance 22'! andthe'lower winding of relay 22!, outer upper front contact of relay 223,brush 525 to conductor58l, and the two windings of relay I53. With relayI93 locked, relay 22! operates, in turn operating relay 222 which locksto conductor 3H. Relay 222 connects direct battery to the winding ofrelay 22!, releasing relay I93 in the mannerpreviously described,followed by the release of relay 22!.

Ground on conductor M2 is now extended over the right contact of relay22 I, lower front contact of relay 222, back contacts of relays 226 and225 to conductor 229 and'the armature of relay 290.

Relay 299, which is pulsing at twenty pulses per second, operates relays2'28 and 224 to absorb the first cycle, these relays looking toconductor 229. With relay 225 operated the right contact of relay 299 isconnected'to the winding of the stepping magnet 253 of switch 259 whilethe left contact of 'relay 290 is connected to brush 523 and the ringline conductor. The tens digit is transmitted to the dial equipment andswitch 255 advanced.

The terminals of switch 259 are cross-connected to the terminals ofbrushes 51! and 514 in accordance with the selected designations and,when brush reaches the terminal cross-connected to the first terminal ofbrush 513, a circuit is closed from battery through the winding of relay226, brushes25! and 513, outer'upper back contact of re1ay'655,conductorGHl-to ground as previously traced. Relay 225 locks'tooff-normal contact 255, disconnects ground from conductor 229 to stopthe pulsing and release relays 2124 and 228, connects ground to the ringconductor to holdthe dial equipment, and operates relay 225. Relay 225operates release magnet 254 to restore the switch 259 to normal and addsground to the ring conductor.

Relay 225 connects ground over its outer lower contact to conductor 23%,normal contact and winding of relay'fiflfi to battery. Relay 596 locksto conductor 6! preparing a circuit for relay 695. When switch 25!]returns to normal relay 225 releases and relay 695' operates. Relay 226opens the circuit of relay 225 but that relay releases slowly to permitthe sender to prepare for the neXt digit.

With relay 225 released, conductor 229 is grounded again and the unitsdigit is sent out; At this time the circuit of relay 226 extends overbrushes 25! and 57!, outer upper back contact of relay 691, outer upperfront contact of relay 695 to ground over conductor 6|9. When relay 225is operated by the arrival of brush 25! at the cross-connected terminal,the same operations take place as at the end ofthe tens digit. However,the connection of ground to conductor 23!] now completes a circuit overthe inner upper front contact of relay 655 to the windings of relays59'! and 698 which operate in the manner of relays G93 and 694.

The operation of relay 6% opens the locking circuit of relay 226,permitting thatrelay to release, and'closes a circuit from ground onconductor 3E9, upper'front contact of relay 658, conductor 5!'!, backcontact of relay 223, brush 525 to conductor 58! and the windings ofrelay I93. Relay Hi3 operates and locks as previously described.

With relays 555 and 59? operated, ground on conductor 5 I 9 extends,over the outer upper front contacts of relays 555 and 55?, to conductor983 and the winding of relay 992. The operation of relay 992 is now anindication that the tens and units digit dialing circuit has completedits operation. The circuit for operating relay 994 is, therefore, thesame asrbefore this latter dialing circuit was started. Relay 9 i '9looks under the control of relays 55!, 953, 595 and 551 while relay 992looks under the control of relay Sit. Relay 994 opens the lockingcircuits of relays 555 to 698 used in this circuit as well as those ofthe relays looked under its control in its other circuits.

When an additional number of cycles have taken place, key 89! is againoperated to stop the circuit, key 855 is operated and key 89'! released.

Line disconnect circuit The operation of key 593 connects the backcontact of magnet 53'! in parallel with the other magnet contacts in thecircuit of relay 203. It also connects ground over its inner uppercontact to the outer lower armature of relay 199 to provide an operatingcircuit for magnet 531, and relay 9i2 which is closed when relay 15!]operates.

Relay 9S2 locks in a circuit from battery through its lower winding andlower contact, conductor 9H, inner lower-back contact of relay 904 togrounded conductor 892. When relay 109 releases, ground from the contactof key 8513 extends over the outer lower back contact of relay 789,conductor H9, upper contact of relay 9I2, right, normal, contact ofrelay 995, back contact of relay 9M, winding of relay 9H5 and battery.Relay 9l5 locks to conductor 9!'!.

With relay 9H5 operated a circuit is closed from battery throughresistance 9 63, lower winding of relay 995, upper contact of relay 9!6,conductor 9l9, brush 533, conductor 58!, lower winding of relay N33 toground over the upper locking contact of relay I53. Relay 99B operatesin this circuit, closing a circuit from ground on conductor H0, uppercontact of relay 9l2, left, operated, contact of relay 9%, outer lowercontact of relay 9H5 to the winding of relay 9M and battery. Relay 5Moperates and locks to conductor 9!'!.

Relay 9M connects direct battery in shunt of resistance 9H3, causingrelay I93 to release, in turn releasing relay 9%. No circuit is providedto hold the dial equipment at this time, therefore the switchesconnected with line terminals I90 and ID! are permitted to restore.

When relay 999 releases, a circuit is closed from ground on conductorH9, upper contact of relay 9!2, right contact of relay 950, upper frontcontact of relay 9M. to the winding of relay 920 and battery. Relay S29.operates and locks in a circult from battery through its lower windingand contact to ground over conductor 258'.

With key 858operated the circuit for relay 994 used following the startof the tens and units dialing circuit is opened and a circuit closedwhich depends on the completion of its cycle by each of the five circuitunits. This circuit may be traced from battery through the winding ofrelay 994, conductor 955, upper contact of relay 929, lower alternatecontactof key898, innerLupper contact of relay 9H], upper contact ofrelay 992, conductor 9! inner lower alternate contact of key 809,

lower front contact of relay 404, upper alternate contact of key 895,conductor 806, inner upper front contact of relay 2!! to groundedconductor 802.

The circuit now proceeds to originate calls on the line terminals, oneafter another. Lamp 90'! provides a visual indication of the speed withwhich the complete calls are put through while the line lamp, such aslamps I05 and !25, provide an indication of the spacing between theoperations of the various units.

When it is desired ot stop the circuit, key 800 is released releasingall relays which may be locked at the time. Switches which areoif-normal may be restored by means of the stepping keys individualthereto which receive ground from key 800 in its normal position.

Terminals 2!5, 2I6 and (M3 to M6 are used to control the dialing ofirregular designations such as permanent signal, zero operator orpartial di-' aling. To omit the corresponding digit, terminal 2 I6 iscross-connected to the desired terminal of brush 553 or 554, terminal2!5 to the terminal of brush 55! or 552, terminal 5!3 to that of brush563 or 554 and so on.

For example, if a permanent signal condition is to be sent, in aparticular position of switches 55!), 56c and 5%, all of thecross-connecting terminals 255, M5 and M3 to GIG will be connected tothe brush terminals in this position. Therefore, as soon as relay 235has operated and relay 293 reoperated, grounding conductor 2H, as abovedescribed, a circuit will extend from conductor 25'! over the lower backcontact of relay 2l3, brush 553, terminal 2H5 to the windings of relays2 l3 and 2 M which operate immediately.

With relays 2i 3 and 2M operated a circuit is closed from ground at thelower front contact of relay 2 !3, brush 55!, terminal 2 !5, uppercontact of relay 2M to conductor 2 9 to operate relay 404. Similarly,when switch 550 reaches the corresponding position, the operation ofrelays 253 and 2555 closes a circuit over conductor 5H), back contact ofrelay 86!, brush 563, terminal 6! 3 to the windings of relays 6%)! andSE32 which operate at once. Relay 66! extends the circuit to brush 565and terminal 6M thereby operating relays 853 and tea to in turn operateSill. In a similar manner relays 505 to 608 are operated to in turnoperate relay 982. The release and reoperation of the line relay takesplace whether or not the digits are transmitted. While in the circuitshown provision has been made for two digit office codes the adaptationfor use in a three digit o-ffice-would be made readily.

It may be noted that since switche 560, am, 523, 53:; and 54s havetwenty-five sets of terminals and switches 55%, 56!! and 570 have twentytwo sets of terminals, different designations will be transmitted eachtime a line is seized until each designation has been sent out over eachline.

What is claimed is:

1. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, and means to operate said equipmentin simulation of service conditions comprising means for automaticallyconnecting with and closing a particular plurality of said lines one ata time, other means for connecting with said lines and transmittingpredetermined telephone designations over said lines in turn andadditional means for connecting with each of said lines and opening saidlines in turn.

2. In a telephone system, automatic switching equipment, lines havingaccess to said switching 7 equipment, and means to operate saidequipment in simulation of service conditions comprising means forautomatically connecting with and closing a particular plurality of saidlines one at a time, means efiective after a predetermined number ofsaid lines have been closedfor connecting with said lines andtransmitting predetermined telephone designations over said lines inturn and means effective after a further predetermined number of lineshave been closed for connecting with each of said lines and opening saidlines in turn.

3. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, and means to operate said equipmentin simulation of service conditions comprising means for automaticallyconnecting with and closing a particular plurality of said lines one ata time, means effective after a predetermined number of said lines havebeen closed for connecting with said lines and transmittingpredetermined telephone designations over said lines in turn, meansefi'ective after a further predetermined number of lines have beenclosed for connectlng with each of said lines and opening said lines inturn, and manual means for predetermining said number of lines and saidfurther number of lines.

4. In telephone system, automatic switching equipment, lines havingaccess to said switching equipment, and means to operate said equipmentin simulation of service conditions comprising means for successivelyoriginating a call, dialing an ofiice code, dialing a numerical code andterminating a call over each of said lines at predetermined overlappingintervals and means for maintaining said intervals throughout theoperation of said equipment.

5. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, and means to operate said equipmentin simulation of service conditions comprising call originating means,means for connecting each of said lines in turn with said calloriginating means to originate a call thereover, a plurality of dialingmeans, means for connecting each of said dialing means with each of saidlines in turn to transmit a telephone designation thereover, callterminating means, means for connecting said call terminating means witheach of said lines in turn, manual means for controlling the relativetime of connection of said call originating means, said dialing meansand said call terminating means with the first of said lines and meansfor automatically advancing said connecting means and maintaining saidrelative time of connection with the remainder of said lines.

6. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, and means to operate said equipmentin simulation of service conditions comprising call control meansincluding as elements call originating means, a plurality of dialingmeans and call terminating means, connecting means for connecting eachelement of said call control means to said lines'in turn and means tocontrol said connecting means to simultaneously connect each element ofsaid call control means with difierent lines.

7. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, and means to operate said equipmentin simulation of service conditions comprising means for successivelyoriginating a call,

dialing an ofiice code, dialing a numerical code and terminating a callover each of said lines at predetermined overlapping intervals, meansfor maintaining said intervals throughout the operation of saidequipment, and means for controlling said dialing means to dial adifierent office code: and numerical code in connection with callsoriginated over successive lines and with successive calls on any one ofsaid lines,

8. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, means to operate said equipment insimulation of service conditions comprising means for automatically andrepeatedly closing aparticular plurality of said lines one at a time,means for transmitting telephone designations over said lines in turn,means for automatically opening said lines in turn, and means forcontrolling said designation transmitting means to transmit a differenttelephone designation over each of said lines following each closure ofsaid lines.

9. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, means to operate said equipment insimulation of service conditions comprising a plurality of sets of lineterminals connected to a plurality of said lines, a relay individual toeach said set of line terminals, a plurality of multiposition switches,means to operate said switches to successively connect with each set ofline terminals and the relay individual thereto in turn, means tooperate each of said relays to close a bridge across the correspondingset of line terminals, means controlled over each of said switches ineach position to release the connected said relay and substitute adialing connection for said bridge, means to transmit a plurality ofdigits over said dialing connection, and means to reoperate said relayto restore said bridge.

10. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, means to operate said equipment insimulation of service conditions comprising a plurality of sets of lineterminals connected to a plurality of said lines, a relay individual toeach said set of line terminals, a pluralityof multiposition switches,means to operate said switches to successively connect with each set ofline terminals and the relay individual thereto in turn, means tooperate each of said relays to close a bridge across the correspondingset of line terminals, means controlled over each of said switches ineach position to release the connected said relay and substitute adialing connection for said bridge, means to transmit a plurality ofdigits over said dialing connection, means to reoperate said relay torestore said bridge, an additional switch having access to said lineterminals and means operated over said additional switch to release eachof said relays in turn.

11. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, means to operate said equipment insimulation of service conditions comprising a plurality of sets of lineterminals connected to a plurality of said lines, a plurality ofmulti-position rotary switches having access to said line terminals,means controlled over each switch for establishing a dialing connectionwith eachset of line terminals in turn, a plurality of other rotaryswitches having a different number of positions, means effective in eachposition of said other switches for controlling said dialing connections in accordance with different telephone designations, andmeans'for advancing one of said multiposition switches and one of saidother switches simultaneously through a plurality of rotations to dial aplurality of different designations over each set of line terminals.

12. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, and means to operate said equipmentin simulation of service conditions comprising call control meansincluding as elements call originating means, a plurality of dialingmeans and call terminating means, connecting means for connecting eachelement of said call control means to said lines in turn, means in eachof said elements responsive to the operation of said element forpreparing the associated connecting means for advance, and means underthe joint control of the responsive means in all of said elements tosimultaneously advance all of said connecting means.

13. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment, and means to operate said equipmentin simulation of service conditions comprising call control meansincluding as elements call originating means, a plurality of dialingmeans and call terminating means, connecting means for connecting eachelement of said call control means to said lines in turn, manual meansfor successively starting each of said elements, means in each of saidelements responsive to the operation of said element for preparing theassociated connecting means for advance, means to advance saidconnecting means, and means under the control of said manual means forsuccessively placing said advancing means under the joint control of theresponsive means of the elements which have been started.

14. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment and means to operate said equipmentin simulation of service conditions comprising call originating means,first connecting means for connecting said call originating means witheach of said lines in turn to establish a bridge across each line tooriginate a call thereover, the first means operated responsive to theestablishment of said bridge to control the advance of said firstconnecting means to the next line, a plurality of dialing means, otherconnecting means for connecting each of said dialing means to each ofsaid lines to transmit a telephone designation thereover, other meansoperated responsive to the completion of each of said dialing operationsto control the advance of said other connecting means to the next line,call terminating means, aditional connecting means for connecting saidcall terminating means with each of said lines in turn to disconnectsaid bridge, further means responsive to the disconnection of saidbridge to control the advance of said additional means to the next line,manual means for controlling the relative time of connection of saidfirst connecting means, said other connecting means and said additionalconnecting means with the first line of said plurality of lines, andmeans for automatically maintaining said relative time of connection foreach of said lines.

15. In a telephone system, automatic switching equipment, lines havingaccess to said switching equipment and means to operate said equipmentin simulation of service conditions comprising call originating means,first connecting means for connecting said call originating means witheach of said lines in turn to establish a bridge across each line tooriginate a call thereover, the first means operated responsive to theestablish ment of said bridge to control the advance of said firstconnecting means to the next line, a plurality of dialing means, otherconnecting means for connecting each of said dialing means to each ofsaid lines to transmit a telephone designation thereover, other meansoperated responsive to the completion of each of said dialing operationsto control the advance of said other connecting means to the next line,call terminating means, additional connecting means for connecting saidcall terminating means with each of said lines in turn to disconnectsaid bridge, further means responsive to the disconnection of saidbridge to control the advance of said additional means to the next line,manual means for controlling the relative time of connection of saidfirst connecting means, said other connecting means and said additionalconnecting means with the first line of said plurality of lines, andmeans operated under the joint control of said first responsive means,said other responsive means and said additional responsive means tosimultaneously advance all of said connecting means.

LLOYD T. MEEDS.

